code: def test_reset(self):
      self._metric.cat_acc = MagicMock()
      self._metric.reset({})
      self.assertTrue(self._metric.cat_acc.reset.call_count == 1)
  
file_path: torchbearer/tests/callbacks/test_mixup.py
imports: from unittest import TestCase
  from mock import patch, call, MagicMock
  import torch
  import torchbearer
  from torchbearer.callbacks import Mixup, MixupAcc
label_desc: Use image node_id 4 for calling the TestMixupAcc obj's underlying member method code with example usage: obj.test_reset() without return types